Abstract：The soil and soil organic carbon (SOC) erosion in three typical terrestrial ecosystems (natural forest, barren land and restored forest) were investigated using 137Cs. Study sites were located in Xiaoliang of Guangdong province. Soil 137Cs inventories and SOC content were measured; the 137Cs distribution and the relationships between 137Cs and SOC were analyzed. The natural forest was the reference site of the study region. In the natural forest, the average activity of 137Cs in 0~40 cm soil horizon was (0.99±0.28) Bq/kg, 137Cs reference inventory was (448.1±56.3) Bq/m2, and SOC storage of 0~40cm horizon was 5.93 kg/m2. 137Cs was undetected in soils of the barren land and the restored forest. Heavy soil erosion had occurred on the barren land and the restored forest. In the natural forest, the distribution of 137Cs in profile had a non-exponential decrease shape with depth while the peak values of 137Cs concentration occurred in the sub-surface horizon. The correlation between 137Cs activity and SOC content in different soil layers of the natural forest was non-significant (P>0.1). 137Cs reference inventory was very low in the study region. The calculation of the soil and SOC erosion by using 137Cs in the study area or other relevant areas would be limited.
